Finding an Optimal Latency for Paired Associative Stimulation in People With Chronic Stroke

Overview

This trial is active, not recruiting.

University of Minnesota - Clinical and Translational Science Institute

Start date

September 2014

End date

May 2015

Trial size

3 participants

Trial identifier

NCT02188420, DPT_PAS

Summary

After a stroke, there is an exaggerated inhibitory influence from the non-stroke hemisphere
to the stroke hemisphere. Brain stimulation using repetitive transcranial magnetic
stimulation (rTMS) to the non-stroke hemisphere can decrease this inhibition. Paired
Associative Stimulation (PAS) may be a more effective way to produce this same inhibition,
as shown in healthy subjects. However, it is not known whether this will translate to people
with stroke. PAS consists of a peripheral nerve stimulus paired a short time later with a
cortical stimulus to change the excitability within the brain. Thus the investigators will
apply PAS to people with stroke, but the investigators need to first determine the most
effective interpulse interval (IPI) between the peripheral and cortical stimuli. Our
research question is which of three different IPIs is most effective in changing the
excitability of the brain.

The purpose of this study is to determine the optimal IPI between a peripheral nerve pulse
and a cortical stimulus that will be most effective in changing excitability of the brain in
people with chronic stroke. The investigators hypothesize that the cortical excitability of
the nonstroke hemisphere will be most inhibited with the latency-5ms condition.

Study Design

Transcranial Magnetic Stimulation will be applied to the primary motor cortex at the interstimulus interval of ("Latency" - 3ms) where "latency" refers to the amount of time for the arrival of a sensory evoked potential as determined by EEG.

Transcranial Magnetic Stimulation will be applied to the primary motor cortex at the interstimulus interval of ("Latency" - 5ms) where "latency" refers to the amount of time for the arrival of a sensory evoked potential as determined by EEG.

Transcranial Magnetic Stimulation will be applied to the primary motor cortex at the interstimulus interval of ("Latency" - 7ms) where "latency" refers to the amount of time for the arrival of a sensory evoked potential as determined by EEG.

Transcranial Magnetic Stimulation will be applied to the primary motor cortex at the interstimulus interval of ("Latency" + 100ms), known to have no effect, where "latency" refers to the amount of time for the arrival of a sensory evoked potential as determined by EEG.

transcranial magnetic stimulation (magstim)
TMS

Primary Outcomes

Measure

Change in cortical excitability using single TMS pulses

time frame:
Change from pretest (immediately prior to PAS application) to posttest which will occur over the 60 minutes that follow PAS application.

Additional Information

Official title

Effect of Different Interpulse Intervals of Paired Associative Stimulation on Cortical Excitability in People With Chronic Stroke

Principal investigator

Kate Frost, MS

Description

Numerous PAS studies have been done in healthy subjects and all have been done safely. The
proper interpulse interval in healthy individuals between the peripheral nerve stimulus and
the cortical stimulus is known to be "latency-5ms." However, this may be different in
individuals with stroke.
Specific Aim: what is the optimal interpulse interval to achieve the maximum inhibitory
effect in the nonstroke hemisphere?
We will recruit three subjects with chronic stroke. Electroencephalography (EEG) will be
used to determine the latency between the peripheral nerve stimulus and the sensory evoked
potential in each subject. We will then assess the following IPIs on each subject in a
random order: "latency" - 3ms, -5ms and -7ms. There will be a fourth condition of "latency"
+ 100ms (known to have no effect) to be used as a control. The washout period will be at
least one week between each of these conditions.
The optimal IPI will be determined from these tests by comparing single pulse transcranial
magnetic stimulation (TMS) measures for cortical excitability. Prior to each treatment, each
subject will receive 20 single pulse cortical stimuli to serve as pretest data. The post
tests for each condition will consist of 20 single pulse cortical stimuli at 0, 5, 10, 15,
30, 45 and 60 minutes after the PAS condition. Data analysis will consist of a
single-subject analysis with the two standard deviation bandwidth method of each post-test
compared to pre-test.
We hypothesize that there will be no adverse advents and that this optimal IPI will be
"latency"-5ms.

Trial information was received from ClinicalTrials.gov and was last updated in February 2016.

Information provided to ClinicalTrials.gov by University of Minnesota - Clinical and Translational Science Institute.